The invention relates to a process for the preparation of 5-fluorotoluene-2,4-disulphochloride by chlorosulphonation of 3-fluorotoluene.
It is known from J. Pharm. Pharmacol., 12, 419 (1960) and J. Org. Chem., 27, 951 (1962) to react 3-fluorotoluene with chlorosulphonic (chlorosulfuric) acid. Disadvantages in this process are the inadequate yields of approximately 50% of theory and the large excess of chlorosulphonic acid which is employed.